Salinity research and rehabilitation

Student activities

Exercise 1: Students investigate the effect that salt has on plants.

Assist students to identify the independent variable (What they will change), dependent variable (What they will measure/ observe) and control variables (Things that will stay the same) in the following scientific investigation.

  • In five separate cups place five or sixwheat seeds into dampened soil. Cover with plastic wrap to assist germination then keep moist and allow the plants to grow until they reach two leaf stage and are approximately 10cm high.
  • Fill one 600ml water bottle with clean water. In the remaining four bottles mix water with increasing amounts of salt. Start with 1/2 tsp of salt, 1tsp, 2tsp, 5tsp. Label the bottles and cups.
  • Record the effect that different solutions have on the plant through observation and measurement of plants. Taking photo’s at regular intervals may help with visual observations.

Teacher notes: Dissolved salts found in water and soil are easily absorbed by the roots of plants and transported to the leaf margins where they ‘burn’ the leaves. Soils with high levels of salt hinder the plant’s ability to uptake water and nutrients resulting in poor growth. Burning occurs on leaf tips and margins —yellowing progresses to brown and then black. Leaf shed and ‘die-back’ of growing tips can also occur and young plants can become stunted. Plants showing symptoms of salt damage will have thicker than normal leaves and appear a darker green as well as being stunted. Grasses appear dark green with burning on the margins (DAFWA, 2015).

Exercise 2: Year 5/6 students - The Walton family has managed to restrict encroaching salinity on their Yealeringbroadacre property by planting saltbush. View the following video on their efforts:

youtube.com/watch?v=8UCv_Ih-hBw

Exercise 3: Year 5/6 Students - Use pictures and/or words to complete a flow chart to show how dryland salinity has occurred and some strategies farmers use to rehabilitate their land. Suggestions and prompts below.

Reflection

Solving an issue as extensive as salinity requires collaboration between landowners and many other professionals. Can you list some of the people who work in research and rehabilitation?

What sort of tasks or jobs do landowners and professionals need to do to determine if salinity is a problem and the best way to manage that salinity?